Cohort 1: n=20 women with insertion dates 3-5months prior to enrollment and followed for 2-6 months Cohort 2:n=20 women with insertion dates 9-11 months prior to enrollment and followed for 2-6 months Cohort 3: n=250 women with insertion dates 21-24 months prior to enrollment and followed through month 36 Cohort 4:n=300 women with insertion dates 33-36 months prior to enrollment and followed through month 6